Android:无法接收 BottomSheetDialog 状态更改回调

Question

我已经像这样实现了 BottomSheetDialog:

addLinkSheet = new BottomSheetDialog(this);
addLinkSheetView = getLayoutInflater().inflate(R.layout.dialog_quickadd_wagrouplink, null);
addLinkSheet.setContentView(addLinkSheetView);
addLinkSheet.show();

我正在尝试使用此代码收听 Bottom Sheet (展开/折叠/隐藏)的状态变化:

BottomSheetBehavior behavior = BottomSheetBehavior.from((View)addLinkSheetView.getParent());
    behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            Toast.makeText(QuickAddWaGroup.this, "State changed", Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onSlide(@NonNull View bottomSheet, float slideOffset) {

        }
    });

我的 BottomSheet 显示正确，但我从未看到状态的 Toast 被更改。我做错了吗？

Answer 1

您必须将回调包装在 BottomSheetDialog 的 OnShowListener 中，它应该可以工作:

bottomSheetDialog = new BottomSheetDialog(this);
View contentView = getLayoutInflater().inflate(R.layout.bottom_content_view, null);
bottomSheetDialog.setContentView(contentView);
bottomSheetDialog.setCancelable(true);
bottomSheetDialog.setOnShowListener(new DialogInterface.OnShowListener() {
    @Override
    public void onShow(DialogInterface dialogInterface) {
        bottomSheetBehavior = BottomSheetBehavior.from((View)contentView.getParent());
        bottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
            @Override
            public void onStateChanged(@NonNull View bottomSheet, int newState) {
                if (newState == BottomSheetBehavior.STATE_EXPANDED) {
                    Log.d(TAG, "State Expanded");
                    // ... do whatever is required on 'expanded'
                } else if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                    bottomSheetDialog.dismiss();
                }
            }

            @Override
            public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                if (bottomSheetBehavior.getState() == BottomSheetBehavior.STATE_EXPANDED) {
                    if (Math.abs(slideOffset) > 0) {
                        bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
                        bottomSheetBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);
                    }
                }
            }
        });

        bottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
    }
});

// Get your contentView children set here...
bottomSheetDialog.show();

关闭 Bottom Sheet 对话框；你将需要:

bottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
bottomSheetBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);

这将再次触发 onStateChanged 事件并关闭对话框。